KR102347011B1 - Method for generating preamble symbol, method for receiving preamble symbol, method for generating frequency domain symbol, and apparatuses - Google Patents

Abstract

The present invention provides a method for generating and receiving a kind of preamble symbol, a method for generating a related frequency domain symbol and a related apparatus, and a procedure for generating a cyclic prefix based on a partial time domain main body signal obtained from a time domain main body signal. ; generating a modulated signal based on part or all of the partial time domain main body signal; and generating a time-domain symbol based on at least one of the cyclic prefix, the time-domain main body signal and the modulated signal, wherein the preamble symbol includes at least one of the time-domain symbols. , when all or a part of a constant length of the time domain main body signal is used as a prefix, coherent detection can be realized, and the degradation of non-coherent detection performance and the failure of differential decoding under complex frequency selective fading channels are solved. , as a post-fix modulation signal based on all or part of the cut time domain main body signal, so that the generated preamble has good fractional frequency offset estimation performance and timing synchronization performance.

Description

A method and apparatus for generating and receiving a preamble symbol, and a method and apparatus for generating a frequency domain symbol

The present invention relates to the field of communication technology, and more particularly, to a method and apparatus for generating and receiving a preamble symbol and a method and apparatus for generating a frequency domain symbol.

In general, in order to accurately demodulate data transmitted by a transmitting end to a receiving end of an OFDM system, the OFDM system must realize accurate and reliable temporal synchronization between the transmitting end and the receiving end. In addition, since the OFDM system is very sensitive to the frequency offset of the carrier, the receiving end of the OFDM system needs to further provide an accurate and efficient carrier frequency estimation method, which can accurately estimate and correct the frequency offset of the carrier.

Currently, the signal of the OFDM system is composed of physical frames, and every physical frame has a sync frame head, which is referred to as a preamble symbol or a bootstrap. Realize phase synchronization. The preamble symbol is a symbol sequence that both the receiving end and the transmitting end of the OFDM system already know, and is generally referred to as a PI symbol. The PI symbol or bootstrap symbol includes the following uses.

1) The transmitting end quickly detects whether the signal transmitted in the channel is the desired received signal or not, and confirms it.

2) Basic transmission parameters (number of FFT points, frame type information, etc.) are provided so that the receiving end can perform subsequent reception processing.

3) After detecting and compensating for the initial carrier frequency offset and timing error, frequency and timing synchronization are realized.

4) Perform an emergency alert or wake-up of the broadcasting system.

At present, for example, in the DVB_T2 standard, based on the already existing PI symbol design of the time domain structure, the above functions are well realized. However, the low complexity reception algorithm also has certain limitations. For example, in a long multipath channel of 1024, 542, or 482 symbols, coarse synchronization of timing creates relatively large deviations and introduces errors in estimating carrier integer multiples of frequency offsets in the frequency domain. . Also, among complex frequency selective fading channels, for example, during long multipath channels, DBPSK differential decoding may fail. In addition, since there is no cyclic prefix in the DVB_T2 time domain structure, when channel estimation is performed using a preamble symbol, the frequency domain channel estimation performance may be severely degraded.

According to the present invention, in the conventional DVB_T2 standard and other standards, the time domain structure of the preamble symbol of the DVB_T2 standard is not suitable for coherent detection, and DBPSK differential decoding of the preamble symbol among the complex frequency selective fading channels fails, so the reception algorithm It is intended to solve the problem that there is a probability of failure in detection.

In order to solve the above problems, an embodiment of the present invention provides a method for generating and receiving a preamble symbol, a method for generating a related frequency domain symbol, and a related apparatus as described below.

<Method 1>

An embodiment of the present invention provides a method of generating a kind of preamble symbol, the method comprising: a procedure of generating a cyclic prefix based on a partial time-domain main-body signal cut out from the time-domain main-body signal; generating a modulated signal based on part or all of the partial time domain main body signal; and generating a time-domain symbol based on at least one of a cyclic prefix, a time-domain main body signal, and a modulated signal, wherein the preamble symbol includes at least one of the time-domain symbols.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, a time domain symbol is generated based on a sequentially arranged cyclic prefix, a time domain main body signal, and a modulated signal, and the preamble symbol includes at least one of the time domain symbols.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the cyclic prefix and the modulated signal generation procedure are obtained by directly cutting the prefix from the rear part of the time domain main body signal, and modulating all or part of the partial time domain main body signal corresponding to the cyclic prefix to obtain a modulated signal includes procedures.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the procedure for generating the cyclic prefix and the modulated signal includes: a procedure of generating a cyclic prefix by processing a portion cut out from the rear part of the time domain main body signal according to the first predetermined processing rule; and a procedure for generating a modulated signal by processing a portion cut out from the rear part of the time domain main body signal according to a second predetermined processing rule, wherein the first predetermined processing rule is a direct copy or one same fixed coefficient or different coefficients. and multiplying by , wherein the second predetermined processing rule includes: performing modulation processing when the first predetermined processing rule is a direct copy; Alternatively, when the first predetermined processing rule is to multiply one same fixed coefficient or a different predetermined coefficient, the modulation processing is performed after multiplying the corresponding coefficient as well.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the length of the modulated signal does not exceed the length of the cyclic prefix.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the procedure of generating a modulated signal using the partial time domain main body signal includes a procedure of setting a frequency shift sequence; and multiplying part or all of the partial time domain main body signal by the frequency shift sequence to obtain a modulated signal of the time domain main body signal.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the modulation frequency offset value of the frequency domain sequence is determined by the frequency domain subcarrier interval corresponding to part or all of the partial time domain symbol or the length of the modulated signal, and the initial phase of the frequency domain sequence is an arbitrary value.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the preamble symbol transmits signaling information in the following manner, and when a combination of a length of a cyclic prefix and a length of a modulated signal is determined, it is necessary to cut off the partial time domain main body signal when generating a modulated signal. and transmits different signaling information using different starting positions at the time of cutting.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the length of the time domain main body signal is 2048 sampling cycles, the length of the cyclic prefix is 520 sampling cycles, the length of the modulated signal is 504 sampling cycles, and the starting position at which the modulated signal is cut out of the time domain main body signal. is the 1544th sampling.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, P1_A(t) is the time domain representation of the time domain symbol, N _A is the length of the time domain main body signal, Len _C is the length of the cyclic prefix, Len _B is the length of the modulated signal, f _SH is a modulation frequency offset value for performing modulation on the time domain main body signal, and when T is set as a sampling period, the preamble symbol is a time domain symbol including a cyclic prefix, a time domain main body signal and a modulation signal. The area notation formula is as follows.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, if the length N _A of the time domain main body signal is 2048, the length of the cyclic prefix Len _C is 520, and the length Len _B of the modulated signal is 504, the cyclic prefix of the preamble symbol, the time domain main body signal and the modulated signal are The time domain representation of the included time domain symbol is as follows.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the time domain main body signal represents emergency information with at least one bit signaling, and when the modulated signal of the modulated signal length is cut from the time domain main body signal according to different starting positions, the emergency information is transferred to the different starting positions. indicate information.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the time domain main body signal is obtained by processing based on the frequency domain symbol.

Optionally, the method for generating a preamble symbol provided above further includes the following features. Among them, the procedure for generating a frequency domain symbol includes a procedure for arranging a fixed sequence and a signaling sequence respectively generated in the frequency domain and then charging the signal on an effective subcarrier.

<Method 2>

An embodiment of the present invention provides a method for generating a frequency domain symbol, wherein the method arranges a fixed sequence and a signaling sequence separately generated in the frequency domain, and then charges it on an effective subcarrier for a frequency domain symbol of a predetermined length. It is characterized in that it includes a procedure for forming a.

Optionally, the method for generating a frequency domain symbol provided above further includes the following features. The method further includes determining an average power ratio of the fixed sequence and the signaling sequence, and generating the fixed sequence and the signaling sequence, respectively, according to the average power ratio.

Optionally, the method for generating a frequency domain symbol provided above further includes the following features. Among them, the value of the average wave power ratio between the fixed sequence and the signaling sequence is 2.

Optionally, the method for generating a frequency domain symbol provided above further includes the following features. Among them, the fixed sequence and the signaling sequence are arranged according to a predetermined cross-alignment rule, wherein the predetermined cross-alignment rule includes any one of the following two rules; or a part of the signaling sequence is placed on an odd subcarrier, another part is placed on an even subcarrier, a part of the fixed sequence is placed on an odd subcarrier, and another part is placed on an even subcarrier.

Optionally, the method for generating a frequency domain symbol provided above further includes the following features. Among them, the signaling sequence generation procedure includes: a procedure for generating the same sequence generation formula based on a preset length and number of signaling sequences; a procedure of generating different fixed-amplitude zero autocorrelation sequences by selecting different phase basis values based on the same sequence generation equation; and selecting a signaling sequence from among every fixed-amplitude zero autocorrelation sequence based on the determined length of the signaling sequence.

Optionally, the method for generating a frequency domain symbol provided above further includes the following features. Among them, the signaling sequence generation procedure includes: a procedure for generating a plurality of sequence generation equations based on a preset length and number of signaling sequences; a procedure for generating a corresponding fixed-amplitude zero autocorrelation sequence by selecting different phase basis values for each sequence generation equation; and selecting a signaling sequence from among every fixed-amplitude zero autocorrelation sequence based on the determined length of the signaling sequence.

Optionally, the method for generating a frequency domain symbol provided above further includes the following features. Among them, the method further includes the following procedure with respect to the generated fixed-amplitude zero autocorrelation sequence, and further includes a procedure of further cyclically shifting the generated fixed-amplitude zero autocorrelation sequence.

<Method 3>

An embodiment of the present invention provides a method of receiving a preamble symbol, and is characterized by including the following procedure. The method includes a procedure for processing a received signal; a procedure of determining whether a desired reception preamble symbol is present in the processed signal; and if it is determined that there is, a procedure for determining the position of the preamble symbol and obtaining signaling information possessed by the preamble symbol.

Optionally, the provided preamble symbol receiving method further includes the following features. Among them, the procedure of determining whether a desired reception preamble symbol exists in the processed signal, and determining the location of the preamble symbol and obtaining the signaling information of the preamble symbol when it is determined that there is, is any of the following at least one procedure That is, it includes an initial timing synchronization method, an integer multiple frequency offset estimation method, a precise timing synchronization method, a channel estimation method, a decoding result analysis method, and a fractional frequency offset estimation method.

Optionally, the provided preamble symbol receiving method further includes the following features. Among them, it is determined whether a desired reception preamble symbol is present in the signal after processing using at least one of the following results, and the results are initial timing synchronization, integer multiple frequency offset estimation, precise timing synchronization, channel estimation, decoding analysis, and segmentation. Multiple frequency offset estimation method is included.

Optionally, the provided preamble symbol receiving method further includes the following features. Among them, the procedure for determining whether a desired reception preamble symbol is present in the signal includes a procedure for initially determining the position of the preamble symbol in an initial timing synchronization method; and a procedure of determining whether a desired reception preamble symbol exists in the processed signal based on the result of the initial timing synchronization method.

Optionally, the provided preamble symbol receiving method further includes the following features. Among them, the initial timing synchronization method includes a first type initial timing synchronization method and a second type initial timing synchronization method, and the first type initial timing synchronization method includes any of three characters: a cyclic prefix, a time domain main body signal, and a modulation signal. performing necessary inverse processing on the received signal after processing by using the correlation between the two and/or delay-shifting autocorrelation after signal demodulation to obtain a cumulative correlation value; and after performing delay relationship matching and/or specific mathematical calculation based on the cumulative correlation value, the obtained processing value is used for initial timing synchronization and the position of the preamble symbol is initially determined, or, or the second type initial timing synchronization method is , when any time domain main body signal among the preamble symbols includes a known signal, the difference calculation is performed on the time domain main body signal according to the predetermined N difference values, and the difference calculation is also performed on the time domain signal corresponding to the known information. , and cross-correlating them to obtain N group differential correlation results corresponding to the N difference values one by one, and perform initial synchronization based on the N group differential correlation results, obtain a processing value, and initially Used to determine the position, among which N≥1, among which, when completed based on the first initial timing synchronization method and the second initial timing synchronization method, weight calculation is performed on each obtained processing value, and the weight calculation is performed value completes the initial timing synchronization.

Optionally, the provided preamble symbol receiving method further includes the following features. Among them, the procedure for determining the position of the preamble symbol and obtaining the signaling information of the preamble symbol is obtained after converting all or partial time domain signals of the preamble symbols and/or all or partial time domain signals of the preamble symbols. and a procedure for obtaining signaling information of the preamble symbol by using a frequency domain signal.

Optionally, the provided preamble symbol receiving method further includes the following features. The frequency domain symbol for generating the received preamble symbol includes a procedure of arranging a fixed sequence and a signaling sequence and then charging an effective subcarrier, and also performing integer multiple frequency offset estimation or channel estimation using the fixed sequence Further comprising, the procedure of performing integer multiple frequency offset estimation or channel estimation using the fixed sequence includes: a procedure of cutting out a signal including all or part of a fixed subcarrier according to the position of the preamble symbol that has been initially determined; Integer-multiple frequency offset estimation or channel estimation is performed by calculating for a signal including all or part of the fixed subcarrier and a frequency domain subcarrier sequence, or an integer multiple frequency by performing calculation on a time domain signal corresponding to the fixed subcarrier sequence It includes a procedure for performing offset estimation or channel estimation.

<device 1>

In addition, an embodiment of the present invention provides an apparatus for generating a kind of preamble symbol, and is characterized in that it includes the following units. a cyclic prefix generating unit that generates a cyclic prefix based on the partial time domain main body signal cut out from the time domain main body signal; a modulated signal generating unit for generating a modulated signal based on a part or all of the partial time domain main body signal; and a preamble symbol generating unit configured to generate a time domain symbol based on at least one of a cyclic prefix, a time domain main body signal, and a modulated signal, wherein the preamble symbol includes at least one of the time domain symbols.

<Device 2>

In addition, an embodiment of the present invention provides an apparatus for generating a kind of frequency domain symbol, and is characterized by including the following units. a sequence generating unit that generates a fixed sequence and a signaling sequence in a frequency domain, respectively; and a frequency domain symbol generating unit for arranging the fixed sequence and the signaling sequence and then filling the effective subcarrier to form a frequency domain symbol of a predetermined length.

<device 3>

In addition, an embodiment of the present invention provides a kind of preamble symbol receiving apparatus, characterized in that it includes the following units. a reception processing unit for processing a reception signal; a judging unit for judging whether a desired reception preamble symbol exists in the obtained processed signal; and a positioning analysis unit for determining the position of the preamble symbol and obtaining signaling information possessed by the preamble symbol when it is determined that there is.

Compared with the prior art, the technical solution of the present invention has the following advantages.

In the method for generating and receiving a preamble symbol, and the method and related apparatus for generating a frequency domain symbol provided by an embodiment of the present invention, when the time domain main body signal is an OFDM symbol, all or a constant length of the time domain main body signal part as a prefix, coherent detection is performed using the generated prefix, non-coherent detection performance is degraded, and DBPSK differential decoding fails under complex frequency selective fading channels. A modulated signal is generated using all or a part of the time domain main body signal of one prefix length, and the generated preamble symbol has good fractional frequency offset estimation performance and timing synchronization performance.

In addition, according to the request for transmission efficiency and reliability, a time domain symbol having a three-stage structure is selectively transmitted to be a preamble symbol, and when the preamble symbol includes a symbol having a three-stage structure, based on the same OFDM symbol main body, the Signaling, for example, emergency broadcast, hook information, transmitter notation information, or other transmission parameters, is transmitted to the second part obtained by cutting from the first part to a different cutting starting point in time.

1 is an explanatory diagram of a time domain symbol of a first type three-stage structure in an embodiment of the present invention.
2 is an explanatory diagram of a time domain symbol of a second type three-stage structure in an embodiment of the present invention.
Fig. 3 is an explanatory diagram of an acquisition process based on a time domain symbol of the first type three-stage structure in the embodiment of the present invention;
Fig. 4 is an explanatory diagram of an acquisition process based on time-domain symbols of the second type three-stage structure in the embodiment of the present invention;
5 is an explanatory diagram in which the frequency domain structure 1 is arranged according to the first predetermined cross-arranging rule in the embodiment of the present invention.
6 is an explanatory diagram in which the frequency domain structure 1 is arranged according to the second predetermined cross-arranging rule in the embodiment of the present invention.
7 is a logical explanatory diagram of a correlation result to be detected corresponding to a three-tier structure CAB in a method of receiving a preamble symbol in an embodiment of the present invention.
8 is a logical explanatory diagram of a correlation result to be detected corresponding to a three-stage structure CAB in a method for receiving a preamble symbol in an embodiment of the present invention.

{how to create}

The present embodiment provides a kind of preamble symbol generation method, the preamble symbol generation method comprising:

a procedure of generating a cyclic prefix based on a partial time-domain main-body signal taken from the time-domain main-body signal;

generating a modulated signal based on part or all of the partial time domain main body signal; and

and generating a time domain symbol based on at least one of a cyclic prefix, a time domain main body signal, and a modulated signal, wherein the preamble symbol includes at least one of the time domain symbols.

1 is a display diagram of a time domain symbol of a first type three-stage structure in an embodiment of the present invention. 2 is an explanatory diagram of a time domain symbol of a second type three-stage structure in an embodiment of the present invention.

The generated preamble symbol is,

a time domain symbol having a three-tier structure of the first type; or

It includes a time domain symbol having a three-tier structure of the second type.

A time domain structure of a time domain symbol included in the preamble symbol will be described with reference to FIGS. 1 and 2 . The time domain structure includes a three-stage structure, and there are two types of the three-stage structure, namely, a first type three-stage structure and a second type three-stage structure.

As shown in Fig. 1, the first type three-stage structure has a time domain main body signal (part A) and a prefix (part C) generated using a partial time domain main body signal cut from the time domain main body signal. and a modulated signal, that is, a postfix (part B) generated using a part or all of the partial time domain main body signal.

As shown in Fig. 2, the second type of three-stage structure has a time domain main body signal (part A) and a prefix (part C) generated using a partial time domain main body signal cut from the time domain main body signal. and a hyper prefix (part B) generated using the partial time domain main body signal.

Specifically, a time domain main body signal of a paragraph (indicated by A in the drawing) is taken as the first part, and a part is taken from the first end of the first part by a predetermined acquisition rule, and is processed according to the first predetermined processing rule and copying the first part to the front part to create a third part (indicated by C in the drawing), to use it as a prefix, and at the same time to take a part from the rear part of the first part according to a predetermined acquisition rule, and to perform a second predetermined process Process according to the rules and copy it to the rear of the first part, or copy it to the front part of the prefix after processing to create a second part (indicated by B in the figure), respectively, as a postfix or a hyper prefix, respectively, A first type three-layer structure (CAB structure) with B as a postfix shown in Fig. 1 is generated, and a second type three-level structure (BCA structure) shown in Fig. 2 with B as a hyper prefix is generated, respectively.

In the specific rules for processing the third part and the second part obtained in the first part, the first predetermined processing rule is a direct copy; or multiplying every sampling signal of the taken portion by one same fixed coefficient or a predetermined different coefficient. The second predetermined processing rule includes: performing modulation processing when the first predetermined processing rule is a direct copy; Alternatively, when each sampling signal of the portion taken by the first predetermined processing rule is multiplied by one same fixed coefficient or a different predetermined coefficient, the corresponding portion is also multiplied by the corresponding coefficient and then modulation processing is performed. That is, when the third part is a prefix obtained by direct copying, the second part is a postfix or hyper prefix obtained by modulating the corresponding main body part, and when the third part is multiplied by a corresponding coefficient, the first The two parts are also multiplied by coefficients and modulated, and then post-fix or hyper-prefix.

Fig. 3 is an explanatory diagram of an acquisition process performed for a time domain symbol of the first type three-stage structure in the embodiment of the present invention;

In this embodiment, stage C is a direct copy of stage A, stage B is a modulation signal stage of stage A, and as shown in FIG. 3, the length of A is 1024, the length of cut C is 520, and the length of B is 504, and when constant processing is performed for C and B, each sampling of the signal is multiplied by one fixed coefficient, or each sampling is multiplied by one different coefficient.

The data range of B does not exceed the data range of C, that is, the range of the portion A selected for the modulation signal stage B does not exceed the range of the portion A that is cut off to be C. Preferably, the sum of the length of B and the length of C is the length of A.

Let N _{A be} the length of A, Len _C be the length of C, and let Len _B be the length of the modulation signal terminal B. Set the index of the sampling point of A to 0,1,… Let N _A -1 be, the first sampling point index for generating the modulated signal end part B out of A is N1, and the last sampling point index for generating the modulated signal end part B out of A is N2. The first sampling point index and the second sampling point index satisfy the following predetermined constraint relationship.

In general, the modulation performed on stage B of the second part is frequency offset modulation, that is, multiplies by one frequency shift sequence and modulates with M sequence or other sequence, etc. In this embodiment, taking the modulation frequency offset as an example, P1_A If (t) is the time domain representation of A, the time domain representation of the first type CAB three-tier structure is as follows.

Among them, the time domain main body signal is an OFDM symbol, and the modulation frequency offset value f _SH can be selected as the frequency domain subcarrier interval corresponding to the time domain OFDM main body symbol, that is, 1/N _A T, where T is the sampling period. , N _A is the length of the time domain OFDM main body symbol, in this example, N _A is 1024, and f _SH = 1/1024T. In addition, the initial phase of the frequency shift sequence is an arbitrary value, and f _SH can be selected as 1/(Len _{B T) so that the correlation peak value is sharp.}

As shown in Figure 3, N _A =1024; Len _C =520, Len _B =504, N1 =520. _{At this time, let N A} be the autocorrelation delay with the same content in stage CA _{, N A} +Len _B as the autocorrelation delay containing the same content in stage CB, and autocorrelation delay including the same content in stage AB. Let be Len _B.

In another embodiment, the length of stage C and the length of stage B are exactly the same, that is, stage B can be regarded as a complete adjustable frequency offset stage of stage C.

Specifically, the cyclic prefix C is spliced to the front part of the time domain OFDM symbol A as a guard interval, and the modulated signal terminal B is spliced to the rear part of the OFDM symbol to form a modulation frequency offset sequence, Creates a time-domain symbol of the structure. For example, when N _A =1024, the specific notation is as follows.

4 is an explanatory diagram of processing of a time domain symbol of a second type three-stage structure in an embodiment of the present invention.

Similarly, the time domain notation formula of the time domain symbol of the second type three-stage structure is as follows, and in order to make the processing method of the receiving end more consistent, the modulation frequency offset value in the BCA structure is opposite to the CAB structure, and the modulation frequency offset The initial phase of the sequence is an arbitrary value.

As shown in Figure 4, N _A =1024; Len _C = 520, Len _{B = 504, N1 = 504. At this time, let N A} be the auto-correlation delay with the same content in the CA stage _{, and Len B} as the auto-correlation delay containing the same content in the BC stage. , the autocorrelation delay containing the same content in stage BA is delayed by N _A +Len _B.

In addition, when the preamble symbol includes one three-stage structure symbol, whether it includes the first type three-stage structure or the second type three-stage structure, it is based on the same OFDM symbol main body, In this way, signaling can be transmitted through a time domain structure.

Signaling is transmitted using a different starting point selected from the first part, and the second part is selected from the first part, and when generating the modulated signal, different signaling transmission is realized by cutting the partial time domain symbol to a different starting point position. .

For example, emergency broadcast, hook information, transmitter marking information, or other transmission parameters.

For example, in the first type three-step structure, for example, the predetermined length is 1024, Len _C is 512, and Len _B is 256.

Among them, N1 may take 512+i*16 0≤i<16, indicating 16 different acquisition methods, indicating that a 4-bit signaling parameter is transmitted. Different transmitters may transmit a notation corresponding to the transmitter by taking a different N1, and the same transmitter may transmit parameters by modifying N1 in a time division manner.

Also, for example, an emergency broadcast mark EAS_flag may be transmitted using 1-bit signaling.

If EAS_flag = 1, take N1 = 512-L, that is, N _A is a sampling point in which the corresponding index of the OFDM symbol of 1024 is 512-L ~ 1023-2L, and generates B after modulating the frequency offset sequence, , placed behind A.

If EAS_flag = 0, take N1 = 512 + L, that is, N _A is the sampling point of the corresponding index 512 + L ~ 1023 of the OFDM symbol of 1024, and after modulating the frequency offset sequence, B is generated, placed on the back

The value of L is taken as 8.

Specifically, N _A = 1024, Len _C is 520, Len _B is 504, when N1 = 520, EAS_flag = 0, and when N1 = 504, EAS_flag = 1; Alternatively, when N1=504, EAS_flag=0 is displayed, and when N1=520, EAS_flag=1 is displayed.

Also, for example, N _A = 2048, Len _C is 520, Le _CB is 504, when N1 = 1544, EAS_flag = 0, and when N1 = 1528, EAS_flag = 1; or N1 = When 1528, EAS_flag=0 is displayed, and when N1=1544, EAS_flag=1 is displayed.

For specific notation,

When EAS_flag = 0, the time domain representation of the C-A-B three-tier structure is as follows.

(N_A = 1024)일 때, 및

(N _A = 1024), and

(N_A = 2048)일 때

When (N _A = 2048)

When EAS_flag = 1, the time domain representation of the C-A-B three-tier structure is as follows.

(N_A = 1024)일 때, 및

(N _A = 1024), and

(N_A = 2048)일 때

When (N _A = 2048)

In addition to displaying the emergency broadcast with the second part cut off from a different starting point in the first part, when the preamble symbol contains only one type of three-tier structure, the emergency broadcast can also be displayed with a different three-tier structure. For example, sending a first type three-level structure C-A-B to indicate EAS_flag=0, sending a second type three-level structure B-C-A to indicate EAS_flag=1; Alternatively, the first type three-tier structure C-A-B is sent to indicate EAS_flag=1, and the second type three-tier structure B-C-A is sent to indicate EAS_flag=0.

The detection of a single three-tiered time domain symbol uses the delay autocorrelation of CB, CA and BA stages to obtain a peak value. In order to be able to add the autocorrelation values of the time-domain symbols, and to obtain more reliable performance, the parameters of each of the two three-tiered time-domain symbols are set to N1 (that is, N1 is selected and copied to the modulation signal stage B). The corresponding sampling point index of A) satisfies the following kind of relationship. Let N1 of the first symbol be N1_1, N1 of the second symbol be N1_2, and N1_1+N1_2=2N _A -(Len _B +Len _C ) must be satisfied. If the modulation used for stage B is a modulation frequency offset, the frequency offset value is opposite.

Number 1 indicates a symbol of the C-A-B structure, and number 2 indicates a symbol of the B-C-A structure. If P1_A(t) is the time domain representation of A1 and P2_A(t) is the time domain representation of A2, then the time domain representation of the time domain symbol having the first type three-tier structure is as follows.

For example, N _A =2048; Len _C =520, Len _B =504, f _SH =1/2048.

In this case, the time domain representation of the time domain symbol having the second type three-stage structure is as follows.

Again for the above example, N _A =2048; Len _C =520, Len _B =504, f _SH =1/2048.

The preamble or bootstrap described above includes not only a time domain symbol having a first type of three-stage structure, but also a time-domain symbol having a second type of three-stage structure. Specifically, the preamble symbol or bootstrap of the present invention is not limited to including only a C-A-B or B-C-A structure, and may include, for example, other time domain structures such as a traditional CP structure.

In addition, the present invention provides a method of generating a frequency domain symbol, and a method of generating a frequency domain OFDM symbol having the following frequency domain structure 1 will be described below.

In addition, when the above-described three-stage time domain structure is combined, there is a fixed correspondence between time and frequency domains. Typically, the time domain main body signal (part A) is formed after inverse Fourier transform of the frequency domain OFDM symbol. It is a time domain OFDM symbol. However, it should be noted that the method of generating a frequency domain symbol provided by the present invention is not limited to using only the three-tiered symbol shown in FIGS. 1 to 7 in the time domain, and other arbitrary time domain structures are not limited thereto. It can be applied to symbols.

P1_X is a corresponding frequency domain OFDM symbol, and P1_X _i is a time domain OFDM symbol obtained after discrete Fourier transform.

Among them, M is the sum of the powers of effective non-zero subcarriers.

In the present invention, two types of different types of frequency domain structures of P1_X will be described.

[Frequency domain structure 1]

First, the frequency domain structure of the first type of P1_X will be described, which is defined as frequency domain structure 1. In the frequency domain structure 1, the method of generating a frequency domain symbol is:

a procedure of generating a fixed sequence and a signaling sequence in a frequency domain, respectively; and

and forming a frequency domain symbol by arranging the fixed sequence and the signaling sequence to fill an effective subcarrier.

In the frequency domain structure 1 of P1_X, the frequency domain OFDM symbol includes three parts, respectively, a virtual subcarrier, a signaling sequence (referred to as SC) subcarrier, and a fixed sequence (referred to as FC) subcarrier.

After arranging the signaling sequence subcarrier and the fixed sequence subcarrier according to a predetermined cross alignment rule, virtual subcarriers are distributed on both sides. The predetermined intersection arrangement rule is any one of the following two rules.

The first predetermined intersecting arrangement rule is to arrange in either a dominant crossing or an odd crossing; and

The second predetermined cross-alignment rule places a partial signaling sequence on an odd subcarrier, a part signaling sequence on an even subcarrier, a part fixed sequence on an odd subcarrier, and a part fixed sequence on an even subcarrier. will do

The first predetermined intersect arrangement rule is a staggered or odd-even crossover arrangement of SCs and FCs, so that FC is placed as a pilot rule, and the second predetermined cross arrangement rule places some SC sequences in odd subcarriers and the rest of the SC sequences. is placed in even subcarriers, and at the same time, some FC sequences are placed in odd subcarriers and the remaining FC carriers are placed in even subcarriers, so that FCs or SCs are all placed in odd or even subcarriers, so that some special multi-path Avoiding all fading under the channel, this arrangement does not increase the complexity of the channel estimation and is therefore a more desirable choice.

The length of the fixed sequence is set to L (that is, the number of effective subcarriers with the fixed sequence is L), and the length of the signaling sequence is set to P (that is, the number of valid subcarriers with the signaling sequence is P), in this embodiment For example, L=P. What is intended to be explained is that when the lengths of the fixed sequence and the signaling sequence are different (eg, P>L), the fixed sequence and the signaling sequence are cross-arranged according to the above rule in a zero supplementary sequence subcarrier manner.

5 is an explanatory diagram in which a signaling sequence subcarrier, a fixed sequence subcarrier, and a virtual subcarrier are arranged according to a first predetermined intersecting arrangement rule in an embodiment of the present invention.

As shown in Fig. 5, the procedure of this preferred embodiment includes filling both sides of an effective subcarrier with constant zero-sequence subcarriers to form a frequency domain OFDM symbol of a predetermined length.

Corresponding to 1024 of _{the length N A} of the time domain main body signal A in the time domain structure, the _{frequency domain length N FFT} formed after Fourier transform FFT is 1024.

Continuing below _{, an example in which the predetermined length of the N FFT} is 1024 is used, the length of the zero-sequence subcarrier is G=1024-LP, and (1024-LP)/2 zero-sequence subcarriers are filled on both sides. For example, if L=P=353, then G=318, charging 159 zero-sequence subcarriers on each side.

The frequency domain OFDM symbol generated by the first predetermined intersecting arrangement rule includes the following procedure.

(11) Fixed sequence generation procedure: The fixed sequence is composed of a plurality of 353 groups, the norm is fixed, and the nth values of the fixed sequence subcarriers are as follows;

Among them, R is a ratio value of the power of FC and SC, and the SC _i norm is fixedly 1.

The radian value of the fixed sequence subcarrier may be determined as the first predetermined fixed subcarrier radian value in Table 1 below.

[Table 1] Table of first predetermined fixed subcarrier radian values (first predetermined intersecting arrangement rule)

In the (12th) signaling generation procedure, the signaling generation procedure includes two types, namely, the following first signaling generation method and second signaling generation method. In this embodiment, the signaling sequence generated in the frequency domain may use any one of the following two schemes, and two specific schemes for generating a signaling sequence will be described in detail below.

First signaling sequence generation method:

1.1 Determine the length and number of signaling sequences;

1.2 Based on the length and number of signaling sequences, a root value in the CAZAC sequence generation equation is determined, wherein the length of the signaling sequence is equal to or less than the root value, and the root value is twice the number of signaling sequences and equal or greater Preferably, the root value is chosen as the length of the signaling sequence.

의 root값을 선택한다. 그중, 시퀀스 길이 L은 root 값과 같거나 작으며, 또한, root 값은 2*num과 같거나 크다. 통상적으로, root값은 소수이다.For example, the sequence length L and the number of signaling are determined. For example, when transmitting N bits, the number of signaling num is 2 ^N , and in the CAZAC sequence generation equation

Select the root value of Among them, the sequence length L is less than or equal to the root value, and the root value is equal to or greater than 2*num. Typically, the root value is a decimal number.

1.3 A CAZAC sequence is generated by selecting different q values, among which the number of q values is equal to the number of signaling sequences, and the sum of any two q values is not equal to the root value, and the generated CAZAC sequence is A cyclic shift is required, and the number of digits of the cyclic shift is determined by the corresponding root value and q value.

For example, num different q ₀ , q ₁ , ... … , q _num-1 is selected to generate a CAZAC sequence.

The sequence after the cyclic shift is as follows.

Among them, k is the number of digits of the cyclic shift.

What is intended to be explained is that the selected q _i (0≤i≤num-1) in the present embodiment must satisfy the following condition. Any two q _i , q _j (0≤i,j≤num-1) _{satisfy q i} +q _j ≠root .

Under the above conditions, it is preferable to select a sequence having a low PAPR of the entire frequency domain OFDM symbol. If L is greater than 2*num, preferably root=L is selected, whereby the autocorrelation value of the sequence becomes zero.

1.4 Based on the determined number of signaling sequences, the signaling sequence is selected from among all CAZAC sequences. What is meant to be explained is that if L = root, there is no need to cut, and the obtained CAZAC sequence can be used directly as a signaling sequence. .

For example, a continuous partial sequence having a length of L is cut off from every sequence out of num sequences, or the entire sequence is used as a signaling sequence.

For example, when the signaling sequence length L=353 and the number num=128, the root may be selected as the closest prime number 353. The value of q is in the range of 1 to 352, and the number of digits for each sequence cyclic shift is in the range of 1 to 353. Of all the selectable signaling sequences, preferably 128 groups are selected, and the q value and the number of cyclic shift digits are as indicated by the q value table of Table 2 and the cyclic shift digit table of Table 3, respectively.

[Table 2] q value table

[Table 3] Circular shift digit table

Second signaling sequence generation method:

2.1 Determine the length and number of signaling sequences;

2.2 Based on the length and number of the signaling sequences, a plurality of root values in the CAZAC sequence generation equation are determined, wherein the length of the signaling sequence is equal to or less than the minimum value among the selected plurality of root values, and the selected plurality of root values are The sum of the root values is equal to or greater than twice the number of signaling sequences. Preferably, the root value is chosen as the length of the signaling sequence.

의 복수의 K개

를 선택한다. 그중, 시그널링 시퀀스 길이 L는 모든 root_k 중의 최소치와 같거나 작으며, 또한 복수의 root_k의 합은 2*num과 같거나 크며, 즉,

이다. 통상적으로, root_k 값은 소수이다.For example, the sequence length L and the number of signaling are determined. For example, when trying to transmit N bits, the number of signaling num is 2 ^N , and the CAZAC sequence generation formula

plural K of

select Among them, the signaling sequence length L is less than or equal to the minimum value _{among all root k , and the sum of the plurality of root k} is equal to or greater than 2*num, that is,

to be. Typically, the root _k value is a prime number.

2.3 For every single root value, a CAZAC sequence is generated by selecting a different q value, among which the number of q values is less than or equal to 1/2 of the corresponding root value, and the number of any two q values is The sum is not equal to the corresponding root value, and the generated CAZAC sequence requires a cyclic shift, and the number of digits of the cyclic shift is determined by the corresponding root value and q value.

에 대해, num_k개 상이한 q₀, q₁,

를 선택하여 CAZAC시퀀스

를 생성한다. 그 중,For example, every

For , num _k different q ₀ , q ₁ ,

Select the CAZAC sequence

to create among them,

, 또한

.

, Also

.

Among the second signaling sequence generation methods, a CAZAC sequence is generated by selecting a different q value for each root value. Therefore, I will not explain it again.

가 반드시 하기 조건을 만족해야 한다는 것이다. 임의의 2개 q_i, q_j(0≤i,j≤num_k-1)은 q_i+q_j≠root_k를 만족한다.What is to be explained is that in this embodiment, selected

must satisfy the following conditions. Any two q _i , q _j (0≤i,j≤num _k -1) satisfy _{q i} +q _j ≠root _{k .}

Under the above conditions, it is preferable to select a sequence having a low PAPR of the entire frequency domain OFDM symbol. Also, preferably, root=L of one of them is selected. Thus, the autocorrelation value of the sequence generated by the root is zero.

2.4 The signaling sequence is selected from every CAZAC sequence based on the determined number of signaling sequences. It is emphasized that if any root = L, the signaling sequence is determined using a CAZAC sequence generated according to a root value whose value is the signaling sequence length.

For example, a continuous partial sequence having a length of L is cut off from every sequence out of num sequences, or the entire sequence is used as a signaling sequence.

For example, L=353 and num=128. The root is preferably selected as 353 according to the first signaling sequence generation equation. Then, q=1,2,… Choose 128. q _i +q _j ≠353, (0≤i,j≤128-1) is satisfied. Later, each sequence is truncated to length 353.

Also, for example, L=350 and num=256. According to the second signaling sequence generation formula, root1 is selected as 353, root2=359, and for root1=353, q=1,2,3,… A total of 128 sequences of 128 are selected, and q _i +q _j ≠353. Also, for root2=359, q=100,101,102,… A total of 128 sequences of 227 are selected, resulting in a total of 256 sequences. Later, each sequence is truncated to a length of 353.

In the following (12) signaling sequence generation procedure, a total of 512 signaling sequences are generated using the second signaling sequence generation equation, that is, Seq ₀ , Seq ₁ , . . . Seq ₅₁₁ is generated, and every signaling sequence Seq ₀ ~ Seq ₅₁₁ takes a half again, that is, -Seq ₀ ~ -Seq ₅₁₁ is taken. Otherwise, it is distinguished whether it is a negative (-) sequence, that is, a total of 10 bits of signaling information is transmitted, and the 512 signaling sequences can be divided into 4 groups by adding them, and each group includes 128 signaling sequences. A sub-procedure of generating 128 signaling sequences is as follows.

First sub-procedure: _{Generate a reference sequence zc i} (n), which is a Zadoff-Chu sequence zc(n) of length N.

A second sub-steps: a zc _i (n) 2 to generate a difference copy zc _i ^* (n) of length 2N.

Third sub-procedure: A sequence of length 353 is truncated from the parent specific start position k _{i in zc i} ^* (n) to generate _{SC i (n).}

N values, u _i, and shift values k _i of the signaling sequences Seq ₀ to Seq ₁₂₇ in each group are determined as predetermined signaling sequence parameter tables in Tables 4 to 7 below, respectively.

N values, u _i, and shift values k _i of the first group sequences Seq ₀ to Seq ₁₂₇ are as shown in Table 4 below.

[Table 4] First group signaling sequence parameters

The procedure for generating the second group sequence Seq ₁₂₈ to Seq ₂₅₅ is the same as that of the first group sequence, and the N values, u _i, and shift value k _i are shown in Table 5 below.

[Table 5] 2nd group signaling sequence parameters

The procedure for generating the third group sequence Seq ₂₅₆ to Seq ₃₈₃ is the same as that of the first group sequence, and the N value, u _i, and shift value k _{i thereof} are shown in Table 6 below.

[Table 6] 3rd group signaling sequence parameters

The procedure for generating the fourth group sequence Seq ₃₈₄ to Seq ₅₁₁ is the same as that of the first group sequence, and the N value, u _i, and shift value k _i are as shown in Table 7 below.

[Table 7] 4th group signaling sequence parameters

(13) In the array charging procedure, the fixed sequence and the signaling sequence obtained in the procedure (11) and (12) are arranged in an alternating even or odd order to fill the virtual subcarrier, and then, the frequency domain OFDM according to the following equation form a symbol

6 is an explanatory diagram in which a signaling sequence subcarrier, a fixed sequence subcarrier, and a virtual subcarrier are arranged according to a second predetermined intersecting arrangement rule in the embodiment of the present invention.

, 시그널링 시퀀스 서브캐리어

가 위치한 기우성 위치는 상호교환 가능하며, 전송성능에 어떠한 영향도 미치지 않는다.As shown in FIG. 6 , the signaling sequence of the first half located on the left side of the dotted line in the drawing is arranged on the odd subcarrier, and the signaling sequence of the other half portion located on the right side of the dotted line in the drawing is placed on the even subcarrier, and located on the left side of the dotted line The fixed sequence of the first half is placed on even subcarriers, and the fixed sequence of the second half located to the right of the dotted line is placed on odd subcarriers. That is, P1_X ₀ , P1_X ₁ , ..., P1_X ₁₀₂₃ are generated according to the second predetermined intersection arrangement rule, SC in the first half is placed on odd carriers, FC is placed on even carriers, and SC in the second half is It is placed on even-numbered carriers, and FC is placed on odd-numbered carriers, and the signaling sequences and fixed sequences of the front and rear portions are exchanged with each other. These fixed sequence subcarriers

, signaling sequence subcarrier

The dominant positions where is located are interchangeable and do not affect transmission performance in any way.

When charging the virtual carrier, that is, the zero-sequence subcarrier, the lengths of the zero-sequence subcarriers charged on the left and right sides may be different, but the difference should not be too large.

A specific optimization example of the frequency domain symbol generated by the second predetermined intersecting arrangement rule is presented below. The frequency domain OFDM symbol generated by the second predetermined intersecting arrangement rule includes the following procedure.

(21st) fixed sequence generation procedure: The fixed sequence generation procedure and the (11th) fixed sequence generation procedure are the same, but _{the value taken by the fixed sequence subcarrier radian value ω n} is the radian value table of the second predetermined fixed subcarrier is determined using , and among them, the second predetermined fixed subcarrier radian value table is as shown in Table 8 below.

[Table 8] Table of fixed subcarrier radian values (according to the second predetermined intersection arrangement rule)

Among the (22) signaling sequence generation procedures, the signaling generation procedure and the (12) signaling generation procedure are the same.

In the (23) arrangement charging procedure, after the signaling sequence and the fixed sequence obtained in the (21) procedure and (22) procedure are alternately arranged in odd or even order again, zero carriers are charged on the left and right sides, and then the following formula A frequency domain OFDM symbol is generated according to

{reception method}

The present embodiment provides a method for receiving a preamble symbol, and the method for receiving a preamble symbol can be applied to a preamble symbol generated by a transmitter using a predetermined generation rule.

Among the predetermined generation rules, when the generated preamble symbol includes all description elements related to, for example, the first type three-stage structure and/or the second type three-stage structure described from the time domain point of view in the present embodiment, and/ Alternatively, in the present embodiment, when all the technical elements related to the frequency domain structure 1 are included, for example, described from the point of view of the frequency domain, the description is not repeated, and in short, the applied predetermined generation processing rule does not lose its generality and is It includes a method of generating a preamble symbol described from the viewpoint and a method of generating a frequency domain symbol described from a frequency domain viewpoint.

The preamble symbol generated by the predetermined generation rule includes the three-stage structure and the frequency domain structure 1, respectively, and a method of receiving the preamble symbol will be described below.

A method of receiving a kind of preamble symbol provided in this embodiment is,

Procedure S11: a procedure of processing a received signal;

Procedure S12: a procedure of determining whether a preamble symbol including the three-stage structure of the desired reception among the processed signals exists; and

Procedure S13: When it is determined that there is, a procedure of determining the position of the preamble symbol and obtaining signaling information of the preamble symbol,

Among them, the received preamble symbol includes a preamble symbol generated by the transmitting end using any number of free combinations of the first type three-stage structure and/or the second type three-stage structure according to a predetermined generation rule, and the preamble symbol is It includes at least one time domain symbol.

The three-stage structure of the first type includes a time domain main body signal, a prefix generated based on all or part of the time domain main body signal, and a post generated based on all or part of the partial time domain main body signal. Includes fix.

The second type three-stage structure includes a time domain main body signal, a prefix generated based on all or part of the time domain main body signal, and a hyper prefix generated based on all or part of the partial time domain main body signal. includes

As described in step S11, the received physical frame signal is processed to obtain a baseband signal. Normally, the signal received by the receiving end is an analog signal, so analog-to-digital conversion (AD conversion) is performed on it to obtain a digital signal. After obtaining, filtering, downsampling, etc. are performed to obtain a baseband signal. What is meant to be explained is that if the receiving end receives an intermediate frequency signal, AD conversion processing is performed on it, and then a frequency spectrum shift is required, and then A baseband signal is obtained by processing such as filtering and downsampling.

As described in step S12, it is determined whether there is a preamble symbol including the three-stage structure of the desired reception among the baseband signals.

Specifically, first, the receiving end determines whether there is a desired reception preamble symbol among the received baseband signals. That is, it is determined whether the received signal meets the reception standard. For example, when the receiving end requests to receive DVB_T2 standard data, it is determined whether the received signal includes the DVB_T2 standard preamble symbol. Similarly, it is determined whether a time domain symbol having a C-A-B and/or a B-C-A three-stage structure is included in the received signal.

When it is determined that the preamble symbol to be received exists in the received signal after the obtained processing, the position of the preamble symbol is determined, and in the procedure of obtaining the signaling information of the preamble symbol, that is, in the procedures S12 and S13, the initial timing and at least one of synchronization, integer multiple frequency offset estimation, fine dimming synchronization, channel estimation, decoding analysis, and fractional frequency offset estimation.

Reliability is determined using the following arbitrary method or a free combination of at least two arbitrary methods, that is, whether a desired reception preamble symbol is present in the processed signal. That is, an initial timing synchronization method, an integer multiple frequency offset estimation method, a precise timing synchronization method, a channel estimation method, a decoding result analysis method, and a fractional frequency offset estimation method are selected.

The procedure S12 includes the initial timing synchronization method of S12-1, the position of the preamble symbol in the physical frame is initially determined, and also includes S12-2, which is based on the result of the initial timing synchronization method. It is determined whether there is a preamble symbol having the three-stage structure of the desired reception in the band signal. The initial timing synchronization method completes the initial timing synchronization by using any one or a combination of the following (①) initial timing synchronization method and (②) initial timing synchronization method.

[(①) Initial Timing Synchronization Method]

The (①) initial timing synchronization method will be described below. (①) Initial timing synchronization method includes the following procedure.

The cyclic prefix, the time domain main body signal, and the modulated signal, and/or the received signal after processing using a processing relationship between any two of these three characters, are subjected to necessary inverse processing and/or delayed-shifted autocorrelation after signal demodulation to obtain a cumulative correlation value; and

After delay relationship matching and/or specific mathematical calculation is performed based on the cumulative correlation value, the obtained processing value is used for initial timing synchronization and the position of the preamble symbol is initially determined.

Among them, in accordance with the processing relationship and/or modulation relationship between the third part C, the first part A and the second part B in the three-stage structure of the desired reception, inverse processing and/or signal demodulation necessary for the baseband signal After delay-shifting autocorrelation, three cumulative correlations between the third part C and the first part A, the first part A and the second part B, and the third part C and the second part B of the three-stage structure Any one or two of the values ie U _ca ^' (n), U _cb ^' (n), U _ab ^{' (n) are obtained.} A correlation value to be detected is obtained based on at least one of the cumulative correlation values.

For example, when the three-stage structure is a C-A-B structure,

Based on the delay relationship between the third part C and the first part A, delay-shifted autocorrelation is performed on the received signal, and the delay correlation notation expression U _ca (n) and the delay correlation cumulative value U _ca ^' (n) are It is as follows.

[Equation 18-1; 18-2]

We can choose to proceed with power normalization for _{U ca} ^'(n).

in other words,

Delay-shifted autocorrelation and demodulation frequency offset are performed on the received signal based on the processing relationship of the second part B and the third part C and the modulation frequency offset value, and the delay correlation notation expression U _cb (n) and the delay correlation accumulation The value U _cb ^' (n) is as follows.

[Equation 20-1; 20-2]

Similarly, we can choose to proceed with power normalization for _{U cb} ^'(n).

Based on the processing relationship of the second part B and the first part A and the modulation frequency offset value, delay-shifted autocorrelation is performed on the received signal, and the delay correlation notation expression U _ab (n) and the delay correlation cumulative value U _ab ^' (n) is as follows.

[Equation 21-1; 21-2]

Similarly, we can choose to proceed with power normalization for _{U ab} ^'(n).

Among them, corr_len may take 1/f _SH T to avoid continuous wave interference, or _{may take Len B} to obtain a sharp peak value.

또는

로써 계산값 즉 검측하려는 상관값 1을 얻는다.Delay matching and mathematical calculations are performed using the accumulated delay correlation values U _ca ^' (n), U _cb ^' (n), U _ab ^' (n), and the mathematical calculations include multiplication or addition, for example ,

or

Thus, the calculated value, that is, the correlation value 1 to be detected, is obtained.

7 is a logical explanatory diagram for obtaining a correlation result to be detected corresponding to a three-layer structure CAB in an embodiment of the present invention.

Among them, C, A, and B in the figure indicate the lengths of the C stage, A stage, and B stage, respectively, and the moving average filter may be a power normalization filter.

Among them, A is N _A , B is Len _B , and C is Len _C . For example, when the three-layer structure is a BCA structure,

Based on the delay relationship between the third part C and the first part A, delay-shifted autocorrelation is performed on the received signal, and the delay correlation notation expression U _ca (n) and the delay correlation cumulative value U _ca ^' (n) are It is as follows.

[Equation 22-1; 22-2]

We can choose to proceed with power normalization for _{U ca} ^'(n).

in other words,

Based on the processing relationship of the second part B and the third part C and the modulation frequency offset value, delay shift autocorrelation and demodulation frequency offset are performed on the received signal, and the delay correlation notation expression U _cb (n) and the delay correlation accumulation The value U _cb ^' (n) is as follows.

[Equation 24-1; 24-2]

Similarly, we can choose to proceed with power normalization for _{U cb} ^'(n).

Based on the processing relationship of the second part B and the first part A and the modulation frequency offset value, delay-shifted autocorrelation is performed on the received signal, and the delay correlation notation expression U _ab (n) and the delay correlation cumulative value U _ab ^' (n) is as follows.

[Equation 25-1; 25-2]

Similarly, we can choose to proceed with power normalization for _{U ab} ^'(n).

Among them, corr_len can take 1/f _SH T to avoid continuous wave interference, or _{take Len B} to get a sharp peak value.

또는

로써 계산값 즉 검측하려는 상관값 2를 얻는다.Delay matching and mathematical calculations are performed using the accumulated delay correlation values U _ca ^' (n), U _cb ^' (n), U _ab ^' (n), and the mathematical calculations include multiplication or addition, for example ,

or

Thus, the calculated value, that is, the correlation value 2 to be detected, is obtained.

8 is a logical explanatory diagram of obtaining a correlation result to be detected corresponding to a three-layer structure BCA in an embodiment of the present invention.

The same parts in FIGS. 7 and 8 require one set of receive sources, and the figures are shown separately for clarity. Among them, C, A, and B in the drawing indicate the lengths of the C stage, A stage, and B stage, respectively, and the moving average filter may be a power normalization filter. Among them, A is N _A and B is Len _B ; C is Len _C.

A correlation value of the initial timing synchronization is formed based on the correlation result 1 to be detected and/or the correlation result 2 to be detected.

In addition, when transmitting the preamble symbol at the same time including the following two situations (a) and (b), that is,

(a) when a known signal is included in the time domain main body signal; and

(b) when it is detected that the time domain symbol has the C-A-B triple structure,

Initial timing synchronization is completed by any one or a combination of any one or two types of the (①) initial timing synchronization method and the (②) initial timing synchronization method below. When two types of synchronization methods are completed, the weighted calculation of the first initial timing synchronization calculated value obtained by the (①) initial timing synchronization method and the second initial timing synchronization calculated value obtained by the (②) initial timing synchronization method and completing the initial timing synchronization based on the weighted calculation value.

[The (②) initial timing synchronization method]

The (②)th initial timing synchronization method will be described below.

Among them, when the main body signal A of any CAB and/or BCA includes a known signal that is, for example, a fixed subcarrier, or, for example, the preamble symbol is a three-stage structure of a plurality of CABs and/or BCAs in the time domain symbols, and among them, when the main body signal A of the parent time domain symbol is a known signal, that is, when any time domain main body signal among the preamble symbols includes the known signal, in the (②) initial timing synchronization method , the difference calculation is performed on the time domain main body signal A according to the predetermined N difference values, the time domain signal corresponding to the known signal is also differentially calculated, and the N difference values of N groups are cross-correlated by correlating them. A result of differential correlation corresponding to each of the values is obtained, and an initial timing synchronization is performed based on the result of the N-group differential correlation to obtain a processing value, and is used to initially determine the position of the preamble. Among them, N≥1.

Below, the specific process of differential correlation among the (②) initial timing synchronization methods will be described. First, the process of single-group differential correlation will be described.

The difference value is determined, the difference calculation is performed on the received baseband data according to the difference value, the difference calculation is performed according to the difference value in the local time domain sequence corresponding to the known signal, and then the difference calculation between these two A result of the differential correlation corresponding to the difference value is obtained by cross-correlating the results of . The calculation process of this single group differential correlation result is a prior art. Assuming that the difference value is D and the received baseband data is r _n , the specific formula for each procedure is as follows.

First, a difference calculation is performed using a difference value with respect to the received baseband data.

으로 변하며, 여기서, Δf는 캐리어 주파수 오프셋을 표시한다.After the difference calculation, the phase rotation caused by the carrier frequency offset is the fixed carrier phase.

, where Δf denotes the carrier frequency offset.

At the same time, differential calculation is also performed on local time-domain sequences (eg, fixed subcarriers are charged to the corresponding positions and the remaining positions are filled with 0, and then IFFT is performed to obtain the corresponding time-domain sequence).

Then, the received data after the difference and the local difference sequence are cross-correlated to obtain the following expression.

A situation in which there is no multi-path and no noise in the system is as follows.

은 아주 양호하게 상관피크를 제공할 수 있으며, 피크값은 캐리어 오프셋의 영향을 받지 않는다. 프레임동기/타이밍동기위치는 하기식으로 얻는다.

can give the correlation peak very well, and the peak value is not affected by the carrier offset. The frame synchronization/timing synchronization position is obtained by the following formula.

As can be seen from the single-group difference calculation process, the differential correlation calculation method can replace the influence of any large carrier frequency offset, but first calculates the difference on the received sequence to enhance the noise of the signal, and S/N When the rain is low, the noise reinforcement is very severe, and the S/N ratio clearly deteriorates.

을 얻는다. 그중, D(0)，D(1)，…, D(N-1)은 선택한 N개의 상이한 차분값이다.In order to avoid the above problem, not only the correlation calculation using the difference value of a single group, but also the differential correlation calculation of multiple groups can be performed, for example, taking the value of N as 64 and the differential correlation of 64 groups by proceeding with

to get Among them, D(0), D(1),… , D(N-1) is the selected N different difference values.

A specific mathematical calculation is performed on the N results to obtain the final correlation result.

In the present embodiment, for a plurality of groups of differential correlations (64 groups), a difference value is selected using any one of the following two predetermined difference selection rules based on the performance requirements of the transmission system.

(1) First predetermined difference selection rule: The difference value D(i) selects N different values and satisfies D(i)<L. Among them, L is the length of the local time-domain sequence corresponding to the known signal.

의 상수 정수를 만족한다. 그중, L는 기지신호에 대응하는 로컬 시간영역 시퀀스의 길이이다.(2) Second predetermined difference selection rule: The difference value D(i) selects N different values of the arithmetic sequence and satisfies D(i)<L, that is, D(i+1)-D(i)= is K, and K is

satisfies the constant integer of . Among them, L is the length of the local time-domain sequence corresponding to the known signal.

A predetermined process calculation is performed on these N results (64 pieces) to obtain a final correlation result. Here, there are two preferred embodiments of the predetermined process calculation, and each will be described.

First predetermined processing calculation:

은 각각 상이하며, 직접 벡터를 더할 수 없어, 가중 후 절대치 합 또는 평균을 취할 수 밖에 없다. 하기 식을 통해 N개의 상이한 차분상관결과에 대해 소정처리계산을 하여 최종차분결과를 얻는다. 하기식은 절대치를 더하여 얻은 최종 차분결과의 예이다.For the difference value D(i), N different values can be arbitrarily selected, and D(i)<L is satisfied. Since the randomly selected difference value is D(i), the phase after each group differential correlation

are different from each other, and cannot add vectors directly, so the absolute sum or average must be taken after weighting. A final difference result is obtained by performing predetermined processing calculations on N different differential correlation results through the following equation. The following formula is an example of the final difference result obtained by adding absolute values.

Second predetermined processing calculation:

을 만족하는 상수 정수 이다.The difference value D(i) can select N different values arbitrarily, satisfying D(i)<L, and also satisfying that D(i) is an arithmetic sequence, that is, D(i+1)-D( i)=K, and K is

It is a constant integer that satisfies .

의 차분상관값을 얻은 후, 재차 인접한 2그룹의 차분상관값에 대해 공액곱셈을 진행하고, 하기 식으로 N-1그룹의 공액곱셈후의 값을 얻는다.With the difference value selected according to the above rule, for example,

After obtaining the differential correlation value of , the conjugate multiplication is performed again on the differential correlation values of two adjacent groups, and the value after the conjugate multiplication of the N-1 group is obtained by the following equation.

을 동일한

로 변화시키며, 얻은 N-1그룹의 RM_i,m을 이용하여 가중 벡터 합 또는 평균을 취하여 최종 차분결과를 얻으며, 제1소정처리 계산보다 더 양호한 성능을 얻는다. 하기식은 벡터를 더하여 얻은 최종 차분결과의 예이다.Through the above conjugate multiplication, the different phases of each original group

the same

, and using the obtained RM _i,m of the N-1 group, the weighted vector sum or average is taken to obtain the final difference result, and better performance than the first predetermined process calculation is obtained. The following formula is an example of the final difference result obtained by adding vectors.

What is intended to be explained is that when the difference value D(i) is obtained using the second predetermined difference selection rule, the final correlation is obtained by taking the weighted vector sum or average using the value after the conjugate multiplication during the second predetermined processing calculation. In addition to obtaining a result, it is also possible to obtain a final correlation result by directly taking the weighted absolute value sum or average for at least two differential correlation results in the first predetermined processing calculation.

The correlation value of the initial timing synchronization is obtained using the calculation R _{dc,m .}

Regardless of whether the (①) initial timing synchronization method is used or the (②) initial timing synchronization method is used, assuming that the desired preamble symbol is included in the received signal, all are within a certain range of the maximum position of the correlation value of the initial timing synchronization. By using the position in the physical frame, the preamble symbol can be set as a position in the physical frame. A value corresponding to this position is used to add to determine whether a desired preamble symbol is included in the received signal, or the position is used to determine a subsequent integer multiple. It is possible to perform operations such as frequency offset estimation and/or decoding, and in addition, it is determined whether a desired preamble symbol is included in the received signal.

Based on the result of the initial timing synchronization, it is determined whether the preamble symbol having the three-stage structure of the desired reception is included in the post-processed signal, that is, the baseband signal. Specifically, it is detected based on the result of the initial timing synchronization. and, when the detection result satisfies a predetermined condition, it is determined that a preamble symbol having a desired three-stage structure is included in the baseband signal. In addition, satisfying the predetermined condition here may refer to determining whether the predetermined condition is satisfied by the result of the initial timing synchronization itself, or if it is not determined whether the condition is satisfied by the result of the initial timing synchronization itself, the subsequent Refers to determining whether a condition is satisfied by other procedures, for example, integer multiple frequency offset estimation and/or decoding results.

Assuming that the determination is made directly according to the initial timing synchronization result, it can be determined whether the predetermined condition is satisfied, and the predetermined condition is to determine whether the maximum value of the calculation result exceeds a threshold value after a specific calculation for the initial timing synchronization result. include

In particular, among the specific embodiments of the first (①) initial timing synchronization method, a predetermined acquisition rule and/or a predetermined According to the processing rule, two groups of accumulated delayed correlation values are obtained, each group has three values, and among these two groups, at least one of the three delayed correlation accumulated values of each group is used to detect two groups of correlation results. Therefore, the result to be detected is detected, and it is determined whether a three-stage structure is included in the preamble symbol and which three-stage structure is included.

For example, if the correlation result to be detected in the first group satisfies the predetermined condition, it is determined that the preamble symbol of the first type three-stage structure exists in the baseband signal, and if the correlation result to be detected in the second group is If the predetermined condition is satisfied, it is determined that the preamble symbol of the second type three-stage structure is present in the baseband signal.

When the transmitter transmits signaling to a different starting point for selecting the second part (ie, post-pixie/modulated signal) from the first part (ie, the time domain main body signal), the initial timing synchronization is any one or any two Emergency broadcasting can be analyzed with a free combination of species, and emergency broadcasting and Distinguish between general broadcast and transmit.

For example, the receiving end performs the procedure of S12-1 included in the above procedure S12 on the multi-path, that is, performs the procedure of initially determining the position of the preamble symbol in an initial timing synchronization method, and a plurality of correlation results to be detected Based on , it is determined whether a desired reception preamble symbol exists and the transmitted time domain signaling is analyzed.

또는

의 절대치에 의해 희망하는 프리앰블이 존재하는지를 판단한다.For example, when a preamble symbol obtains B by cutting a different starting point position of A using N1, the starting point position can be used to transmit Q-bit signaling, and delay shifting autocorrelation of N1 of the parent value is one It can be defined as a branch of Each branch includes the three delay correlation cumulative values. The receiving end simultaneously proceeds with the delayed-shifted autocorrelation branch of different N1 values of ^{2 Q species, and then, 2 Q}

or

It is determined whether a desired preamble exists by the absolute value of .

If any one absolute value does not exceed the threshold, it indicates that there is no desired received signal among the baseband signals. For example, when N1 sends a 1-bit emergency alert or broadcast system indication to 504 or 520, among N1 = 520 indicates a normal preamble symbol, N1 = 504 indicates an emergency alert or a broadcasting system, and proceeds with the S21-1 procedure of two branches.

For example, if the emergency alert broadcasting mark is 0, that is, N1 = 520,

The received signal delays 1024 sampling points to perform moving autocorrelation with the received signal,

The received signal delays 1528 sampling points and performs moving autocorrelation with the received signal after the demodulation frequency offset,

The received signal delays 504 sampling points to perform moving autocorrelation with the received signal after the demodulation frequency offset, and

For example, if the emergency alert broadcasting notation is 1, that is, N1 = 504,

The received signal delays 1024 sampling points and performs mobile autocorrelation with the received signal after the demodulation frequency offset,

The received signal delays 1544 sampling points and performs moving autocorrelation with the received signal after the demodulation frequency offset.

The received signal delays 520 sampling points and performs mobile autocorrelation with the received signal after the demodulation frequency offset.

When determining whether a desired reception preamble symbol exists in the baseband signal as a predetermined condition using the threshold method,

If the maximum correlation value to be detected in the branch of N1 = 520 exceeds the threshold, the baseband signal is declared as a desired signal, and if the preamble symbol appears, EAS_flag = 0. Conversely, if the maximum correlation to be detected in N1 = 504 is If the value exceeds the threshold, it asserts that EAS_flag=1. If both groups do not exceed the threshold, it asserts that the baseband signal is not a desired signal.

When the preamble symbol represents a non-emergency broadcast with one of the first type three-layer structure and the second type three-layer structure, the emergency broadcast is marked with the other one and analyzed as follows.

In step S12-1, according to a predetermined acquisition rule and/or a predetermined processing rule between the two of the C stage, A stage and B stage of the first type three-stage structure and the second type three-stage structure, the two branches of the S12- One procedure is obtained, each branch has three values, and the procedure S12-2 includes detecting a correlation value to be detected in each branch among these two branches. Among them, if the detection result of the first branch satisfies the predetermined condition, it is determined that the three-stage structure of the first type of desired reception exists in the baseband signal, and EAS_flag=0 is expressed; if the detection result of the second branch is if the predetermined condition is satisfied, it is determined that a three-stage structure of the second type of desired reception exists in the baseband signal, and EAS_flag=1 is expressed; if both branches are satisfied, it is determined separately . For example, an emergency broadcast is judged using the clarity of the peak/noise ratio of the two groups.

In addition, after completing initial timing synchronization in a rudimentary manner, fractional frequency offset estimation is performed using the initial timing synchronization results of method (①) and/or method (②).

When the (①) initial timing synchronization method is used, _{the phase of the maximum value among U ca} ^' (n) is taken, the second multiple frequency offset value can be calculated, and again U _cb ^' (n) and U _ab ^' ( After conjugate multiplication of n) (corresponding to CAB structure) or by conjugate multiplication of U _ab ^' (n) and U _cb ^' (nN _A ) (corresponding to BCA structure), the angle corresponding to the maximum is taken, and the third The fractional multiple frequency offset can be calculated. As described above, in FIGS. 7 and 8, the angle in the logical calculation block diagram is an explanatory part for calculating the fractional frequency offset, and is divided into any one or two of the second fractional frequency offset value and the third fractional frequency offset value. Estimate the multiple frequency offset.

에서, 최대치를 취하며, 대응하는 상은

이며, Δf를 계산해 내어 상응한 제1분수배 주파수 오프셋 값으로 전환할 수 있다.When explaining the estimation calculation method of the fractional frequency offset with an example, when using the (②) initial timing synchronization method,

From , taking the maximum, the corresponding phase is

, and can be converted into a corresponding first multiple frequency offset value by calculating Δf.

In transmitting the preamble symbol, any one of the first, second, and third fractional frequency offsets when implementing the necessary features including the (①) initial timing synchronization method and (②) initial timing synchronization method or any combination of at least two to obtain a fractional frequency offset.

What is intended to be explained is that, in the above embodiment, the appropriate delay number is adjusted within a certain range in consideration of the effect of the deviation of the system sampling clock, for example, adding or subtracting 1 to the corresponding delay number of some delay correlators; It obtains itself and 3 delays by adding or throwing 1, and according to the obtained number of delays after adjustment and the corresponding number of delays, a plurality of delay shifting autocorrelation is performed, for example, these three delay numbers are subjected to shifting delay autocorrelation, , the timing offset can be estimated using the correlation result while selecting the value with the most obvious correlation result.

Without loss of generality, if not only the CAB or BCA structure but also other time domain characteristics are included in the preamble symbol, the timing synchronization method of the CAB or BCA structure characteristics is used, as well as the timing for other time domain structure characteristics. Synchronous methods are also used, which do not exceed the scope of the present invention.

Procedure S12-2 includes an initial timing synchronization method, and it is possible to initially determine the position of the preamble symbol in the physical frame. In addition, after initial synchronization, the integer multiple frequency offset estimation is performed on the result obtained based on the initial timing synchronization method.

In addition, when the time domain main body signal A corresponds to the frequency domain structure, the receiving end may perform integer multiple frequency offset estimation using a fixed sequence, that is, the preamble symbol of the present invention is used for integer multiple frequency offset estimation of the following procedure. may be

1) Based on the determined position of the preamble symbol, a signal including a fixed subcarrier is cut.

2) Calculation is performed on the received signal including the fixed subsequence and the frequency domain fixed subcarrier sequence or the corresponding time domain signal of the frequency domain fixed subcarrier sequence to realize integer multiple frequency offset estimation.

Next, an integer multiple frequency offset estimation method based on the initial thymine synchronization result will be described. In the procedure of performing integer multiple frequency offset estimation, any one or a combination of the following two specific methods is included.

In the first integer multiple frequency offset estimation method, according to the result of the initial timing synchronization, a time domain signal of a paragraph including the whole or partial time domain main body signal is cut off, and a frequency sweeping method is used. After the time domain signal is modulated with different frequency offsets, a plurality of N frequency sweeping time domain signals corresponding to the frequency offset values are obtained one by one, and the known time domain obtained by performing Fourier transform on the known frequency domain sequence. After moving and cross-correlating the signal and every frequency-swept time-domain signal, the maximum correlation peak value of the N cross-correlation results is compared, and the frequency offset value for modulating the frequency-swept time-domain signal corresponding to the maximum cross-correlation result. is an integer multiple frequency offset estimation value. and/or;

In the second integer multiple frequency offset estimation method,

According to the result of the initial timing synchronization, the time domain signal of the length of the time domain main body signal is cut and subjected to Fourier transform, and the obtained frequency domain subcarriers are cyclically shifted to different shift values within the frequency sweeping range, and effective The received sequence corresponding to the subcarrier is cut out, a predetermined calculation is performed on the received sequence and the known frequency domain sequence, and then the inverse transform is performed to select from among a plurality of inverse transform results corresponding to the shift value one by one, and the corresponding shift A value is obtained, and an integer multiple frequency offset estimate is obtained by using the correspondence between the shift value and the integer multiple frequency offset estimate value.

For example, the integer multiple frequency offset estimation method will be described in detail below. For example, the time domain main body signal A has the frequency domain structure 1 correspondingly, that is, the frequency domain OFDM symbol is a virtual subcarrier and a signaling sequence, respectively. It includes three parts of a subcarrier (referred to as SC) and a fixed sequence (referred to as FC) subcarrier, and the known frequency domain sequence described below is a fixed subcarrier.

In the first integer multiple frequency offset estimation method, according to the result of initial timing synchronization, a time-domain waveform including part or all of the time-domain main body signal is cut, and a frequency sweeping method is used, that is, a fixed A plurality of time-domain symbols are obtained after modulating different frequency offsets for the partial time-domain waveform in frequency-change increments, for example, corresponding to integer multiples of frequency offset intervals.

Among them, T is the sampling period, and f _S is the sampling frequency. After about base frequency domain sequence filled with a predetermined sub-carrier filling method it is the time domain signal obtained by proceeding the Fourier transform is A2, and the sheets of A1 _y and moving matter with the A2 as a known signal, the maximum correlation peak value A1 _y If is selected, the corresponding modulation frequency offset value y is directly an integer multiple frequency offset estimate value.

, 즉 [-114 ,114]이다.Among them, the frequency sweeping range is the frequency offset range that the system should replace, for example, a frequency offset of plus or minus 500K should be replaced, the sampling frequency of the system is 9.14M, and the main body of the preamble symbol takes a length of 2K. Then, the frequency sweeping range is

, that is, [-114 ,114].

Second integer multiple frequency offset estimation method: According to the position where the preamble symbol detected with initial timing synchronization appears, the main body time domain signal A is cut and FFT is performed, and the frequency domain subcarrier after FFT is within the frequency sweeping range. After performing cyclic shift of different shift values, the receiving sequence corresponding to the effective subcarrier is cut, and some calculation (usually conjugated multiplication or division) is performed using the receiving sequence and the known frequency domain sequence, and the result is IFFT is performed on the data, and a specific calculation is performed on the IFFT result. For example, taking the maximum path power or accumulating a plurality of large path powers. Thus, a plurality of shift values can be obtained through multiple IFFTs to obtain a plurality of group calculation results. Based on the plurality of group results, it is possible to determine which shift value corresponds to the integer multiple frequency offset estimation, and thereby the integer multiple frequency offset value get

A typical determination method selects a shift value corresponding to a group having the greatest power based on the results of a plurality of groups, and uses this as an integer multiple frequency offset value.

When the time domain main body signal A corresponds to the frequency domain structure 1, the following integer multiple frequency offset estimation method may be used.

The frequency domain OFDM symbol is obtained by cutting the time domain main body signal A of the parent symbol among the preamble symbols, performing Fourier transform, and cyclic shifting of the frequency sweeping range is performed on the frequency domain OFDM symbol obtained by transforming the subcarrier. Interval differential multiplication is performed according to the position of the image and the interval of the two fixed sequence subcarriers before and after, and the correlation calculation is performed with the interval differential multiplication value of the known fixed sequence subcarriers to obtain a series of correlation values, corresponding to the maximum correlation value. If we choose a cyclic shift, i.e. correspondingly, we get an estimate of the integer multiple of the frequency offset.

Specific calculation methods of the integer multiple frequency offset estimation are various, and description thereof will be omitted.

In addition, after the integer multiple frequency offset estimation is completed, the frequency offset is compensated, and then the transmitted signaling is analyzed.

In addition, optionally, after completing the integer multiple frequency offset estimation, precise timing synchronization is performed using known information in the preamble symbol.

When the frequency domain structure 1 is used, precise timing synchronization is performed using a fixed subcarrier sequence FC included in one or a plurality of frequency domain symbols.

If the determination result in step S12-3 is “Yes”, the procedure for determining the position of the preamble symbol in the physical frame and obtaining the signaling information of the preamble symbol will be described in detail below. include

The procedure for determining the position of the preamble symbol includes a procedure for determining the position of the preamble symbol in a physical frame based on a detection result that satisfies a predetermined condition; and

and a procedure for determining the position of the preamble symbol according to a relatively large correlation value to be detected or a maximum correlation value to be detected if a desired reception preamble symbol exists.

The procedure for analyzing the transmitted signaling further includes a channel estimation method.

For example, when the frequency domain structure 1 is provided, channel estimation is performed using the received fixed sequence subcarrier signal and the known frequency domain fixed sequence subcarrier and/or the time domain signal obtained after Fourier transform, and similarly, time It may be selected to proceed in the domain and/or frequency domain, and a description thereof will be omitted.

In addition, after obtaining the frame format parameter and/or emergency broadcast content in the preamble symbol, the position of the subsequent signaling symbol or the position of the data symbol is obtained according to the parameter content and the previously determined position of the preamble symbol, thereby obtaining the subsequent signaling symbol or data symbol Analyze

Subsequently, the procedure for obtaining the signaling information of the preamble symbol in procedure S12-3 will be described. In the signaling signal analysis procedure, all or partial time domain waveforms of the preamble symbols and/or all or partial times of the preamble symbols Signaling of the preamble symbol is obtained by using the frequency domain signal after the domain waveform has undergone Fourier transform.

A signaling analysis process for frequency domain structure 1 will be described below.

Calculation is performed using the received signal of the signaling sequence subcarrier and the signaling sequence subcarrier set or the time domain signal corresponding to the signaling sequence subcarrier set to obtain the signaling information possessed by the signaling sequence subcarrier among the preamble symbols. , a signaling sequence subcarrier set is generated based on a known signaling sequence set.

Among them, the signal including the signaling sequence subcarrier is one or more obtained through Fourier transform after cutting out one or more time domain main body OFDM symbols from all or partial time domain waveforms of the received preamble symbols, or preamble symbols frequency domain OFDM symbol. The signaling sequence subcarrier set is a set obtained by filling each signaling sequence among the signaling sequence sets on an effective subcarrier.

_{Specifically, a time domain signal of length N A} corresponding to the main body of one or a plurality of ODFM symbols is cut and Fourier transformed to obtain one or a plurality of frequency domain OFDM symbols, and then, zero carriers are removed to serve as a signaling sub One or a plurality of received frequency domain signaling subcarriers are taken according to the carrier position. A specific mathematical calculation is performed on the channel estimate value and the known signaling sequence subcarrier set to complete the frequency domain decoding function.

이며, max(corr_j)에 대응하는 j를 취하면 곧바로 주파수영역에서 전송한 시그널링 정보를 얻는다.For example, i = 0: M-1 , M is the signaling sub-carrier ^{number, j = 0: 2 P -1} , P is the signaling bits transmitted in the frequency domain, that is, corresponding to the signaling sub-carrier set is total ^P 2 has elements, each element corresponds to a sequence of length M, H _i is a channel estimate value to which every signaling subcarrier corresponds, SC_rec _i is a received frequency domain signaling subcarrier value, and SC _i ^j is a signaling sequence If it is set as the i-th value of the j-th element in the subcarrier set,

and, when j corresponding to max(corr _j ) is taken, signaling information transmitted in the frequency domain is immediately obtained.

Among other embodiments, the process may be performed in the time domain, and after zeros are supplemented at an appropriate position for the known signaling sequence subcarrier set, a frequency domain symbol of a corresponding length is generated, and then, a Fourier transform is performed to perform time domain signaling A set of waveforms is obtained, and synchronous correlation is performed with a received signal in the time domain to obtain an accurate position directly by using the set of waveforms to obtain the maximum absolute value of the correlation value, thereby obtaining signaling information transmitted in the frequency domain. A description is omitted here.

The present embodiment provides an apparatus for generating a preamble symbol, an apparatus for generating a frequency domain symbol, and an apparatus for receiving a preamble symbol described in the above invention. corresponds to the method of generating a preamble symbol, the method of transmitting a frequency domain symbol, and the method of receiving a preamble symbol, respectively, in the above embodiment, and the structure and description elements in the apparatus can be obtained by corresponding conversion from the generating method and the receiving method. omit

The present invention has been presented as described above as a preferred embodiment, but it is not intended to limit the present invention. Any person skilled in the art can change or modify the technical solution of the present invention based on the method and description presented above without departing from the spirit and scope of the present invention. Therefore, without departing from the technical solution of the present invention, any simple modifications, equivalent changes and modifications to the above embodiments according to the technical substance of the present invention are all within the protection scope of the technical solution of the present invention.

Claims (10)

A method for receiving a preamble symbol, comprising:
the procedure for rudimentary processing of the received signal;
a procedure of determining whether a desired reception preamble symbol exists in the signal after rudimentary processing; and
a procedure of determining the position of the preamble symbol and obtaining signaling information possessed by the preamble symbol when it is determined that there is,
The preamble symbol includes at least one time-domain symbol including a first type three-stage structure and at least one time-domain symbol including a second type three-stage structure,
The time domain symbol of the first type three-stage structure includes a sequentially arranged cyclic prefix, a time domain main body signal, and a postfix;
The method for receiving a preamble symbol, characterized in that the time domain symbol of the second type three-stage structure includes a hyper prefix, a cyclic prefix, and a time domain main body signal that are sequentially arranged. The method according to claim 1,
using the relationship between any two of the three characters of the cyclic prefix, the time domain main body signal and the postfix, or any two of the three characters of the hyper prefix, the cyclic prefix and the time domain main body signal A method for receiving a preamble symbol, characterized in that a correlation value is obtained after calculation using the relationship between the two values, and the position of the preamble symbol is determined by performing calculation on the correlation value. The method according to claim 1,
the cyclic prefix is generated based on a partial time-domain main-body signal taken directly from a rear part of the time-domain main-body signal;
The preamble symbol receiving method, characterized in that the postfix or hyper prefix is a modulated signal generated by modulating a part of the partial time domain main body signal. The method according to claim 1,
The length of the time domain main body signal is 2048 sampling cycles, the length of the cyclic prefix is 520 sampling cycles, the length of the postfix or hyper prefix is 504 sampling cycles, and among the time domain main body signals, the A method for receiving a preamble symbol, characterized in that the starting position for cutting the postfix is the 1544th sampling, and the starting position for cutting the hyper prefix in the time domain main body signal is the 1528th sampling. 4. The method according to claim 3,
The procedure for generating the postfix or hyper prefix by modulating on the basis of the partial time domain main body signal,
a procedure for setting a frequency shift sequence; and
and obtaining the postfix or hyper prefix by multiplying a part or all of the partial time domain main body signal corresponding to the cyclic prefix by the frequency shift sequence. A type of preamble symbol receiving apparatus comprising:
a reception processing unit for basicly processing a reception signal;
a judging unit for judging whether a desired reception preamble symbol is present in the signal after rudimentary processing;
a position analysis unit for determining the position of the preamble symbol and obtaining signaling information possessed by the preamble symbol when it is determined that there is,
The preamble symbol includes at least one time-domain symbol including a first type three-stage structure and at least one time-domain symbol including a second type three-stage structure,
The time domain symbol of the first type three-stage structure includes a sequentially arranged cyclic prefix, a time domain main body signal, and a postfix;
The apparatus for receiving a preamble symbol, characterized in that the time-domain symbol of the second type three-stage structure includes a hyper-prefix, a cyclic prefix, and a time-domain main body signal that are sequentially arranged. 7. The method of claim 6,
using the relationship between any two of the three characters of the cyclic prefix, the time domain main body signal and the postfix, or any two of the three characters of the hyper prefix, the cyclic prefix and the time domain main body signal An apparatus for receiving a preamble symbol, characterized in that a correlation value is obtained after calculation using the relationship between the two values, and the position of the preamble symbol is determined by performing calculation on the correlation value. 7. The method of claim 6,
the cyclic prefix is generated by directly copying a partial time domain main body signal cut directly from a rear part of the time domain main body signal;
The post-fix or hyper-prefix is a preamble symbol receiving apparatus, characterized in that it is generated by modulating a part of the partial time domain main body signal corresponding to the cyclic prefix. 7. The method of claim 6,
The length of the time domain main body signal is 2048 sampling cycles, the length of the cyclic prefix is 520 sampling cycles, the length of the postfix or the hyper prefix is 504 sampling cycles, and one of the time domain main body signals is The apparatus for receiving a preamble symbol, characterized in that a start position at which the postfix is cut is a 1544th sampling, and a start position at which the hyper prefix is cut out of the time domain main body signal is a 1528th sampling. 9. The method of claim 8,
The procedure for generating the postfix or hyper prefix by modulating on the basis of the partial time domain main body signal,
a procedure for setting a frequency shift sequence; and
and a procedure for obtaining the postfix or hyper prefix by multiplying a part or all of the partial time domain main body signal corresponding to the cyclic prefix by the frequency shift sequence.

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